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Oxygen stable isotope (δ18O) analysis of marine biogenic carbonates is widely used to study the temperature at which the hard parts precipitated. This technique enables investigation of the environmental conditions experienced by carbonate-shelled organisms throughout their life. We used this approach on four bivalve species from the Coralline Crag Formation (Early Pliocene; UK), where warm- and cold-associated species co-occur in the Ramsholt Member. Our results reveal species-specific differences in reconstructed temperature. Two distinct climatic settings were identified: a cold setting with seafloor temperatures of 7.3 °C in winter and 12.4 °C in summer, and a warm one with seafloor temperatures of 10.4 °C in winter to above 14 °C in summer. These absolute temperatures were calculated using a modelled value of seawater δ18O (+0.1‰) that is open to question, but the disparity in temperatures exists whatever value is used. Interestingly, the reconstructed temperatures for some of the studied species align with those of their modern relatives: Arctica islandica records the coldest temperatures in this dataset, while Centrocardita squamulosa ampla indicates warmer conditions. Aequipecten opercularis , a eurythermal pectinid, exhibited the broadest range of temperatures. The interval during which the Coralline Crag was deposited (c. 4.4‒3.8 Ma) is generally regarded as relatively warm. However, the presence of A. islandica and the absolute seawater temperatures derived from shell δ18O suggest the occurrence of sufficiently long cool periods for the establishment and survival of this long-lived species. Data from specimens of C. squamulosa ampla and A. islandica collected from a single bed point to glacial/interglacial-type climate fluctuation. These results confirm that the presence of A. islandica is a marker for cold temperate environments. These results also confirm that assemblage information is not sufficient to determine palaeoclimatic conditions, and that reconstructed temperatures from shell δ18O can reveal time-averaging in fossil shell beds. [ABSTRACT FROM AUTHOR]

Hematite (α-Fe2O3) is one of the most promising and widely used semiconductors for application in photoelectrochemical (PEC) water splitting, owing to its moderate bandgap in the visible spectrum and earth abundance. However, α-Fe2O3 is limited by short hole-diffusion lengths. Ultrathin α-Fe2O3 films are often used to limit the distance required for hole transport, therefore mitigating the impact of this property. The development of highly controllable and scalable ultrathin film deposition techniques is therefore crucial to the application of α-Fe2O3. Here, a plasma-enhanced atomic layer deposition (PEALD) process for the deposition of homogenous, conformal, and thickness-controlled α-Fe2O3 thin films (<100 nm) is developed. A readily available iron precursor, dimethyl(aminomethyl)ferrocene, was used in tandem with an O2 plasma co-reactant at relatively low reactor temperatures, ranging from 200 to 300 °C. Optimisation of deposition protocols was performed using the thin film growth per cycle and the duration of each cycle as optimisation metrics. Linear growth rates (constant growth per cycle) were measured for the optimised protocol, even at high cycle counts (up to 1200), confirming that all deposition is 'true' atomic layer deposition (ALD). Photoelectrochemical water splitting performance was measured under solar simulated irradiation for pristine α-Fe2O3 deposited onto FTO, and with a α-Fe2O3-coated TiO2 nanorod photoanode. [ABSTRACT FROM AUTHOR]

A series of zinc(II) thioamidate complexes [Zn{SC(iPr)NR}2]n for R = iPr (n = 2) (2), tBu (3) (n = 1), Ph (4) (n = 2) and Cy (5) (n = 2) and one cadmium(II) thioamidate complex [Cd{SC(iPr)NtBu}2]3, (6), were designed and synthesised as single-source precursors for AACVD ZnS and CdS. Solid-state structures of all four zinc(II) compounds revealed distorted tetrahedral or trigonal bipyramidal geometries, with varying tendencies for dimeric association, mediated by {Zn–S} bridging bonds. The thermogravimetric analysis identified the {tBu} derivertive, 3, as the most promising precursor based on its low decomposition onset (118 °C) and clean conversion to ZnS. This was attributed to the greater availability of β-hydrogen atoms promoting the pyrolysis mechanism. The corresponding cadmium thioamide 6 was found to crystallise as a trimetallic molecule which lacked the thermal stability to be considered viable for AACVD. Hence, 3 was used to deposit ZnS thin films by AACVD at 200–300 °C. Powder X-ray diffraction confirmed phase-pure growth of hexagonal wurtzite ZnS, with approximate crystallite sizes of 15–20 nm. Scanning electron microscopy revealed densely packed spherical nanoclusters. The morphology and crystallinity were most consistent for depositions between 250–300 °C. Energy dispersive X-ray spectroscopy indicated slightly sulfur-deficient stoichiometries. [ABSTRACT FROM AUTHOR]

The β-diketiminato calcium and magnesium complexes, [(BDI)MgnBu] and [(BDI)CaH]2 (BDI = HC{C(Me)NDipp}2; Dipp = 2,6-di-isopropylphenyl), react with ortho-carborane (o-C2B10H12) to provide the respective [(BDI)Ae(o-C2B10H11)] (Ae = Mg or Ca) complexes. While the lighter group 2 species is a monomer with magnesium in a distorted trigonal planar environment, the heavier analogue displays a puckered geometry at calcium in the solid state due to Ca⋯H–B intermolecular interactions. These secondary contacts are, however, readily disrupted upon addition of THF to provide the 4-coordinate monomer, [(BDI)Ca(THF)(o-C2B10H11)]. [(BDI)Mg(o-C2B10H11)] was reacted with [NHCIPrMCl] (NHCIPr = 1,3-bis(isopropyl)imidazol-2-ylidene; M = Cu, Ag, Au) to provide [NHCIPrM(o-C2B10H11)], rare C-bonded examples of coinage metal derivatives of unsubstituted (o-C2B10H11)− and confirming the alkaline earth compounds as viable reagents for the transmetalation of the carboranyl anion. [ABSTRACT FROM AUTHOR]

We develop a new approach for the estimation of a multivariate function based on the economic axioms of quasiconvexity (and monotonicity). On the computational side, we prove the existence of the quasiconvex constrained least squares estimator (LSE) and provide a characterisation of the function space to compute the LSE via a mixed-integer quadratic programme. On the theoretical side, we provide finite sample risk bounds for the LSE via a sharp oracle inequality. Our results allow for errors to depend on the covariates and to have only two finite moments. We illustrate the superior performance of the LSE against some competing estimators via simulation. Finally, we use the LSE to estimate the production function for the Japanese plywood industry and the cost function for hospitals across the US. [ABSTRACT FROM AUTHOR]

The reactivity of the racemic N-heterocyclic stannylene [{MeHCN(tBu)}Sn] (1) with the chalcogenide elements O2, S, Se, and Te has been investigated. In the case of the reaction of 1 with molecular oxygen, the cyclic tristannoxane complex [{MeHCN(tBu)}2Sn(μ-O)]3 (3) was isolated and characterised. NMR studies (1H, 13C, and 119Sn) show the formation of D3- and C2- symmetric assemblies. The reaction of 1 with S, Se, and Te, respectively, yielded the cyclo-distannachalcogenide complexes, [{MeHCN(tBu)}2Sn(μ-E)]3 (4: E = S, 5: E = Se, 6: E = Te), again with multinuclear NMR studies proving the formation of C2- and Cs-symmetric assemblies. Single crystal X-ray diffraction studies have been used to elucidate the molecular structures of the products of oxidative addition, 3, 4, 5, and 6. [ABSTRACT FROM AUTHOR]

Bivalves record seasonal environmental changes in their shells, making them excellent climate archives. However, not every bivalve can be used for this end. The shells have to grow fast enough so that micrometre- to millimetre-sampling can resolve sub-annual changes. Here, we investigate whether the bivalve Angulus benedeni benedeni is suitable as a climate archive. For this, we use ca. 3-million-year-old specimens from the Piacenzian collected from a temporary outcrop in the Port of Antwerp area (Belgium). The subspecies is common in Pliocene North Sea basin deposits, but its lineage dates back to the late Oligocene and has therefore great potential as a high-resolution archive. A detailed assessment of the preservation of the shell material by micro-X-ray fluorescence, X-ray diffraction, and electron backscatter diffraction reveals that it is pristine and not affected by diagenetic processes. Oxygen isotope analysis and microscopy indicate that the species had a longevity of up to a decade or more and, importantly, that it grew fast and large enough so that seasonally resolved records across multiple years were obtainable from it. Clumped isotope analysis revealed a mean annual temperature of 13.5 ± 3.8 ∘ C. The subspecies likely experienced slower growth during winter and thus may not have recorded temperatures year-round. This reconstructed mean annual temperature is 3.5 ∘ C warmer than the pre-industrial North Sea and in line with proxy and modelling data for this stratigraphic interval, further solidifying A. benedeni benedeni's use as a climate recorder. Our exploratory study thus reveals that Angulus benedeni benedeni fossils are indeed excellent climate archives, holding the potential to provide insight into the seasonality of several major climate events of the past ∼ 25 million years in northwestern Europe. [ABSTRACT FROM AUTHOR]

The structures of the Group 1 metal aminoalkoxides Li[OCH(CH2CNMe2)2] (1) and K[OCH(CH2CNMe2)2]∙HOCH(CH2CNMe2)2 (2) have been determined. 1 is a hexa­meric drum in which two Li3O3 rings are joined co-facially, whereas 2 is tetrameric and adopts a K4O4 ladder structure, novel for homoleptic potassium alkoxides.

This work demonstrates p-type SnO thin film transistors, where the SnO active layers were deposited with atomic layer deposition (ALD) using the Sn(II) alkoxide precursor, Sn(II) bis(tert-butoxide). The deposition optimisation explores the use of multiple Sn pulses per ALD cycle and the use of an exposure mode (where the pump extraction is paused before the Sn precursor purge) to increase the residence time and allow for more effective saturation of the surface. The fabricated devices required post deposition annealing of the active layer, with device performance further improved by back-channel passivation using ALD Al2O3. The performance of devices deposited using the varying precursor delivery modes has also been compared, with the devices utilizing deposition with multiple Sn pulses and a post deposition anneal at 250 °C achieving an on/off ratio of ∼4 × 104 and field effect mobility (μFE) of 0.6 cm2 (V s)−1. The growth processes present during deposition with the different precursor delivery modes was investigated using fractal geometry and topographical scaling methods, with the poor device performance for the single Sn pulse deposition attributed to 2D lateral island growth. [ABSTRACT FROM AUTHOR]

Obtaining temperature data from the mid-Piacenzian warm period (ca. 3 Ma, Pliocene epoch) is a key factor in outlining the impact of projected anthropogenic climate change. The mid-Piacenzian warm period was a high-CO2 world with a paleogeography similar to modern times. The time interval has been used to validate and improve climate model retrodictions, which in turn enables assessing the predictive strength of these models. Validating climate models requires a large array of robust proxy data. Here, we increase the potential of this proxy database by showing that the extinct tellinid bivalve Angulus benedeni benedeni can be used for stable isotope-based temperature reconstructions. This species is found in the Pliocene sediments of the southern North Sea basin. Oxygen isotope and carbonate clumped isotope measurements on the shell of A. benedeni benedeni resulted in a mean annual temperature reconstruction of 13.5±3.8 °C. This is 2.5 °C warmer than today, 3.5 °C warmer than the pre-industrial North Sea, and in line with global Pliocene temperature estimates of +2–4 °C compared to the pre-industrial climate. Limited amounts of clumped isotope data hindered determining summer and winter temperatures, but the oxygen isotope record shows that the growth band spacing of A. benedeni benedeni allows for sampling at a resolution of 2–3 months. The species could live for up to a decade, and therefore has the potential to be used for multiannual seasonality reconstructions. The pristine nature of the aragonitic shell material was verified through electron backscatter diffraction analysis (EBSD), and backed by light microscopy, X-ray diffraction, and X-ray fluorescence. The various microstructures as obtained from the EBSD maps have been described, and they provide a template of pristine A. benedeni benedeni material to which potentially altered shells may be compared. The bivalve A. benedeni benedeni is suitable for high resolution isotope-based paleoclimatic reconstruction and it can be used to unravel the marine conditions in the Pliocene southern North Sea basin at a seasonal scale, yielding enhanced insights into imminent western European climate conditions. [ABSTRACT FROM AUTHOR]

Oxygen isotope (δ18 O) sclerochronology of benthic marine molluscs provides a means of reconstructing the seasonal range in seafloor temperature, subject to use of an appropriate equation relating shell δ18 O to temperature and water δ18 O, a reasonably accurate estimation of water δ18 O, and due consideration of growth-rate effects. Taking these factors into account, δ18 O data from late Pliocene bivalves of the southern North Sea basin (Belgium and the Netherlands) indicate a seasonal seafloor range a little smaller than now in the area. Microgrowth-increment data from Aequipecten opercularis, together with the species composition of the bivalve assemblage and aspects of preservation, suggest a setting below the summer thermocline for all but the latest material investigated. This implies a higher summer temperature at the surface than on the seafloor and consequently a greater seasonal range. A reasonable (3 ∘ C) estimate of the difference between maximum seafloor and surface temperature under circumstances of summer stratification points to seasonal surface ranges in excess of the present value (12.4 ∘ C nearby). Using a model-derived estimate of water δ18 O (0.0 ‰), summer surface temperature was initially in the cool temperate range (<20 ∘ C) and then (during the Mid-Piacenzian Warm Period; MPWP) increased into the warm temperate range (>20 ∘ C) before reverting to cool temperate values (in conjunction with shallowing and a loss of summer stratification). This pattern is in agreement with biotic-assemblage evidence. Winter temperature was firmly in the cool temperate range (<10 ∘ C) throughout, contrary to previous interpretations. Averaging of summer and winter surface temperatures for the MPWP provides a figure for annual sea surface temperature that is 2–3 ∘ C higher than the present value (10.9 ∘ C nearby) and in close agreement with a figure obtained by averaging alkenone and TEX 86 temperatures for the MPWP from the Netherlands. These proxies, however, respectively, underestimate summer temperature and overestimate winter temperature, giving an incomplete picture of seasonality. A higher annual temperature than now is consistent with the notion of global warmth in the MPWP, but a low winter temperature in the southern North Sea basin suggests regional reduction in oceanic heat supply, contrasting with other interpretations of North Atlantic oceanography during the interval. Carbonate clumped isotope (Δ47) and biomineral unit thermometry offer means of checking the δ18 O-based temperatures. [ABSTRACT FROM AUTHOR]